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000
FXUS63 KUNR 152017
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
217 PM MDT SAT JUN 15 2013

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 149 PM MDT SAT JUN 15 2013

UPPER LEVEL ANALYSIS HAS CLOSED LOW OVER SOUTH CENTRAL CANADA WITH
BROAD RIDGE OVER THE SOUTH CENTRAL CONUS. IN BETWEEN...FAST ZONAL
FLOW IS IN PLACE ACROSS THE NORTHERN PLAINS. AT THE SURFACE...HIGH
PRESSURE IS PARKED OVER WESTERN SOUTH DAKOTA...PRODUCING MOSTLY
SUNNY SKIES. TEMPERATURES ARE IN THE 70S...WITH GENERALLY LIGHT
WINDS.

FOR TONIGHT...SURFACE HIGH PRESSURE WILL SLOWLY SHIFT EAST AS A
WEAK TROF CROSSES THE AREA. BOUNDARY LAYER FLOW WILL TURN LIGHT
SOUTHERLY OVERNIGHT...ALLOWING FOR SOME MOISTURE RETURN TO THE
AREA. STRONG THETA-E ADVECTION OVER THE AREA LATE TONIGHT WILL
LIKELY RESULT IN SOME ISOLATED SHOWERS AND STORMS DEVELOPING OVER
THE BLACK HILLS AREA AND SOUTHWESTERN SOUTH DAKOTA AFTER MIDNIGHT.
LOWS WILL MOSTLY BE IN THE 50S.

ON SUNDAY...UPPER LOW OVER SOUTH CENTRAL CANADA WEAKENS AND SINKS
INTO NORTH DAKOTA...WHILE SURFACE LOW PRESSURE DEVELOPS OVER THE
NEBRASKA PANHANDLE. WEAK INVERTED TROF IS FORECAST TO EXTEND FROM
THE LOW CENTER INTO SOUTHWESTERN SOUTH DAKOTA BY MIDDAY. SHOWER
AND THUNDERSTORM ACTIVITY SHOULD INCREASE SUNDAY MORNING ACROSS
THIS AREA AS MORNING CAP ERODES. WITH CAPE VALUES PROGGED FROM
2000-3000 J/KG DURING THE MIDDAY AND AFTERNOON HOURS...AND SHEAR
VALUES FROM 25 TO 35 KTS...THERE IS A THREAT FOR A FEW SEVERE
STORMS TO DEVELOP ACROSS SOUTHWESTERN INTO SOUTH CENTRAL SOUTH
DAKOTA...WITH LARGE HAIL THE MAIN THREAT. THESE SHOWERS AND STORMS
SHOULD MOVE TO THE EAST AND SOUTHEAST LATE SUNDAY AFTERNOON AND
EVENING. HIGH TEMPERATURES WILL BE IN THE 70S AND LOWER 80S WITH
MAINLY LIGHT WINDS.

&&

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 149 PM MDT SAT JUN 15 2013

 UPPER RIDGE WILL BUILD INTO THE NRN PLAINS BY MID WEEK AS UPPER
LOW DIGS INTO THE PAC NW. WEAK WAVES WORKING THROUGH THE RIDGE
WILL RESULT IN A NEARLY DAILY CHANCE FOR ISOLATED TSTMS. UPPER
RIDGE AXIS SHIFTS EAST OF THE REGION BY LATE IN THE WEEK AS UPPER
LOW MOVES INTO THE NRN ROCKIES...WITH SOUTHWEST FLOW ALOFT
BRINGING BETTER CHANCES FOR TSTMS TO THE REGION. TEMPS WILL BE
NEAR TO SLIGHTLY ABOVE AVERAGE THROUGH THE PERIOD.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON
ISSUED AT 149 PM MDT SAT JUN 15 2013

ISOLATED THUNDERSTORMS POSSIBLE LATE THIS AFTERNOON/TONIGHT FROM
THE BLKHLS INTO SW SD...WITH ADDITIONAL ACTIVITY POSSIBLE SUNDAY
MORNING ON THE PLAINS SOUTH/EAST OF THE BLKHLS. OTHERWISE...VFR
CONDITIONS EXPECTED NEXT 24 HOURS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...15
LONG TERM...JOHNSON
AVIATION...JOHNSON